From 60f745a0334ba40000d0b4c03255fabde510e56e Mon Sep 17 00:00:00 2001
From: Yegor Yefremov <yegorslists@googlemail.com>
Date: Tue, 8 Jan 2019 11:10:49 +0100
Subject: [PATCH] cpu/stm32_common: add support for uart_mode routine
Add support for specifying data bits, stop bits and parity at
runtime.
Introduce feature periph_uart_modecfg for uart_mode() till all
other CPUs implement it.
STM32 L1, F1, F2, F4 supports following modes:
* 7E1, 7E2
* 7O1, 7O2
* 8N1, 8N2
* 8E1, 8E2
* 8O1, 8O2
STM32 L0, L4, F0, F3, F7 supports following modes:
* 6E1, 6E2
* 6O1, 6O2
* 7E1, 7E2
* 7O1, 7O2
* 7N1, 7N2
* 8N1, 8N2
* 8E1, 8E2
* 8O1, 8O2
Use USART_CR1_M1 macro to detect 7-bit support because
even inside one family there could be devices that don't
support 7-bit mode. So just using a family macro is not
enough.
As stated in the datasheets for L0, L4, F0, F3, F7 devices,
data bits can only be changed when UART is disabled (UE=0).
Introduce uart_stop() routine to satisfy this requirement.
STM32 UART adds parity to the MSB of a byte to send. The same
also applies to the received bytes. As a result this bit must
be masked in order to get the pure data.
Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
---
cpu/stm32_common/Makefile.features | 1 +
cpu/stm32_common/include/periph_cpu_common.h | 50 +++++++++++++++
cpu/stm32_common/periph/uart.c | 67 ++++++++++++++++++--
3 files changed, 113 insertions(+), 5 deletions(-)
diff --git a/cpu/stm32_common/Makefile.features b/cpu/stm32_common/Makefile.features
index 13c07298d7..f54d184a87 100644
--- a/cpu/stm32_common/Makefile.features
+++ b/cpu/stm32_common/Makefile.features
@@ -1,6 +1,7 @@
FEATURES_PROVIDED += periph_cpuid
FEATURES_PROVIDED += periph_gpio periph_gpio_irq
FEATURES_PROVIDED += puf_sram
+FEATURES_PROVIDED += periph_uart_modecfg
ifneq (,$(filter $(BOARDS_WITHOUT_HWRNG),$(BOARD)))
FEATURES_PROVIDED := $(filter-out periph_hwrng,$(FEATURES_PROVIDED))
diff --git a/cpu/stm32_common/include/periph_cpu_common.h b/cpu/stm32_common/include/periph_cpu_common.h
index b1f83a032f..fd97fb25a2 100644
--- a/cpu/stm32_common/include/periph_cpu_common.h
+++ b/cpu/stm32_common/include/periph_cpu_common.h
@@ -370,6 +370,56 @@ typedef enum {
STM32_LPUART, /**< STM32 Low-power UART (LPUART) module type */
} uart_type_t;
+/**
+ * @brief Invalid UART mode mask
+ *
+ * This mask is also used to force data_bits_t to be uint32_t type
+ * since it may be assigned a uint32_t variable in uart_mode
+ */
+#define UART_INVALID_MODE (0x8000000)
+
+/**
+ * @brief Override parity values
+ * @{
+ */
+#define HAVE_UART_PARITY_T
+typedef enum {
+ UART_PARITY_NONE = 0, /**< no parity */
+ UART_PARITY_EVEN = USART_CR1_PCE, /**< even parity */
+ UART_PARITY_ODD = (USART_CR1_PCE | USART_CR1_PS), /**< odd parity */
+ UART_PARITY_MARK = UART_INVALID_MODE | 4, /**< not supported */
+ UART_PARITY_SPACE = UART_INVALID_MODE | 5 /**< not supported */
+} uart_parity_t;
+/** @} */
+
+/**
+ * @brief Override data bits length values
+ * @{
+ */
+#define HAVE_UART_DATA_BITS_T
+typedef enum {
+ UART_DATA_BITS_5 = UART_INVALID_MODE | 1, /**< not supported */
+ UART_DATA_BITS_6 = UART_INVALID_MODE | 2, /**< not supported unless parity is set */
+#if defined(USART_CR1_M1)
+ UART_DATA_BITS_7 = USART_CR1_M1, /**< 7 data bits */
+#else
+ UART_DATA_BITS_7 = UART_INVALID_MODE | 3, /**< not supported unless parity is set */
+#endif
+ UART_DATA_BITS_8 = 0, /**< 8 data bits */
+} uart_data_bits_t;
+/** @} */
+
+/**
+ * @brief Override stop bits length values
+ * @{
+ */
+#define HAVE_UART_STOP_BITS_T
+typedef enum {
+ UART_STOP_BITS_1 = 0, /**< 1 stop bit */
+ UART_STOP_BITS_2 = USART_CR2_STOP_1, /**< 2 stop bits */
+} uart_stop_bits_t;
+/** @} */
+
/**
* @brief Structure for UART configuration data
*/
diff --git a/cpu/stm32_common/periph/uart.c b/cpu/stm32_common/periph/uart.c
index 1358300517..7a932b088c 100644
--- a/cpu/stm32_common/periph/uart.c
+++ b/cpu/stm32_common/periph/uart.c
@@ -53,8 +53,15 @@
/**
* @brief Allocate memory to store the callback functions
+ *
+ * Extend standard uart_isr_ctx_t with data_mask field. This is needed
+ * in order to mask parity bit.
*/
-static uart_isr_ctx_t isr_ctx[UART_NUMOF];
+static struct {
+ uart_rx_cb_t rx_cb; /**< data received interrupt callback */
+ void *arg; /**< argument to both callback routines */
+ uint8_t data_mask; /**< mask applied to the data register */
+} isr_ctx[UART_NUMOF];
static inline USART_TypeDef *dev(uart_t uart)
{
@@ -105,8 +112,9 @@ int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
assert(uart < UART_NUMOF);
/* save ISR context */
- isr_ctx[uart].rx_cb = rx_cb;
- isr_ctx[uart].arg = arg;
+ isr_ctx[uart].rx_cb = rx_cb;
+ isr_ctx[uart].arg = arg;
+ isr_ctx[uart].data_mask = 0xFF;
uart_init_pins(uart, rx_cb);
@@ -154,6 +162,53 @@ int uart_init(uart_t uart, uint32_t baudrate, uart_rx_cb_t rx_cb, void *arg)
return UART_OK;
}
+#ifdef MODULE_PERIPH_UART_MODECFG
+int uart_mode(uart_t uart, uart_data_bits_t data_bits, uart_parity_t parity,
+ uart_stop_bits_t stop_bits)
+{
+ assert(uart < UART_NUMOF);
+
+ isr_ctx[uart].data_mask = 0xFF;
+
+ if (parity) {
+ switch (data_bits) {
+ case UART_DATA_BITS_6:
+ data_bits = UART_DATA_BITS_7;
+ isr_ctx[uart].data_mask = 0x3F;
+ break;
+ case UART_DATA_BITS_7:
+ data_bits = UART_DATA_BITS_8;
+ isr_ctx[uart].data_mask = 0x7F;
+ break;
+ case UART_DATA_BITS_8:
+ data_bits = USART_CR1_M;
+ break;
+ default:
+ return UART_NOMODE;
+ }
+ }
+ if ((data_bits & UART_INVALID_MODE) || (parity & UART_INVALID_MODE)) {
+ return UART_NOMODE;
+ }
+
+#ifdef USART_CR1_M1
+ if (!(dev(uart)->ISR & USART_ISR_TC)) {
+ return UART_INTERR;
+ }
+ dev(uart)->CR1 &= ~(USART_CR1_UE | USART_CR1_TE);
+ dev(uart)->CR1 &= ~USART_CR1_M1;
+#endif
+
+ dev(uart)->CR2 &= ~USART_CR2_STOP;
+ dev(uart)->CR1 &= ~(USART_CR1_PS | USART_CR1_PCE | USART_CR1_M);
+
+ dev(uart)->CR2 |= stop_bits;
+ dev(uart)->CR1 |= (USART_CR1_UE | USART_CR1_TE | data_bits | parity);
+
+ return UART_OK;
+}
+#endif /* MODULE_PERIPH_UART_MODECFG */
+
static inline void uart_init_usart(uart_t uart, uint32_t baudrate)
{
uint16_t mantissa;
@@ -301,7 +356,8 @@ static inline void irq_handler(uart_t uart)
uint32_t status = dev(uart)->ISR;
if (status & USART_ISR_RXNE) {
- isr_ctx[uart].rx_cb(isr_ctx[uart].arg, (uint8_t)dev(uart)->RDR);
+ isr_ctx[uart].rx_cb(isr_ctx[uart].arg,
+ (uint8_t)dev(uart)->RDR & isr_ctx[uart].data_mask);
}
if (status & USART_ISR_ORE) {
dev(uart)->ICR |= USART_ICR_ORECF; /* simply clear flag on overrun */
@@ -312,7 +368,8 @@ static inline void irq_handler(uart_t uart)
uint32_t status = dev(uart)->SR;
if (status & USART_SR_RXNE) {
- isr_ctx[uart].rx_cb(isr_ctx[uart].arg, (uint8_t)dev(uart)->DR);
+ isr_ctx[uart].rx_cb(isr_ctx[uart].arg,
+ (uint8_t)dev(uart)->DR & isr_ctx[uart].data_mask);
}
if (status & USART_SR_ORE) {
/* ORE is cleared by reading SR and DR sequentially */
--
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